H-driver DC-to-DC converter utilizing mutual inductance

• US 5,204,809 A
• Filed: 04/03/1992
• Issued: 04/20/1993
• Est. Priority Date: 04/03/1992
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Andresen, Rolf
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US07/863,620
• Time in Patent Office: 382 Days
• Field of Search: 363/16, 363/17, 363/98, 363/132, 363/124
• US Class Current: 363/132
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02P 7/04 by means of a H-bridge circuit

Abstract

Improved conversion efficiency and lower output ripple are achieved by a DC-to-DC converter that uses an H-bridge driver to alternately energize first and second inductors. By alternately energizing the first and second inductors, a higher switching frequency can be maintained allowing for the use of smaller inductors while reducing ripple in the output voltage. The reduced ripple in turn reduces the need for filtering. Additionally, the first and second inductors are wound about a common core such that a mutual inductance exists therebetween. The mutual inductance results in trapezoidal currents in each inductor instead of the typical sawtooth waveforms. This results in still lower ripple in the output voltage.

Claims

1. A DC-to-DC converter for converting an input voltage having a first magnitude into an output voltage having a second magnitude, the output voltage being made available to a load, the DC-to-DC converter comprising:

a first inductor storage means for providing a first current to the load;

a second inductor storage means for providing a second current to the load;

means for alternately coupling and decoupling the first and second inductor storage means to the input voltage such that the first and second inductor storage means alternately charge and discharge the first and second currents, respectively, ad wherein a mutual inductance between said first and second inductor storage means has a coupling coefficient greater than 0.5.

2. The DC-to-DC converter according to claim 1 wherein the means for alternately coupling is an H-bridge driver.

3. A DC-to-DC converter for providing a converted voltage to an output terminal, the DC-to-DC converter comprising:

an H-bridge driver having first, second, third and fourth switching means, said first switching means is a transistor coupled to an input voltage and coupled for receiving a first control signal, said second switching means is a transistor coupled for receiving a second control signal, the second control signal controlling the second switching means for operating substantially 180 degrees out of phase with the first switching means, said third switching means is a transistor coupled to the input voltage and coupled for receiving a third control signal, the third control signal controlling the third switching means such that third switching means is biased open when the first switching means is biased closed and the third switching means is biased closed when the first switching means is biased open, said fourth switching means is a transistor coupled between the third switching means and the reference voltage and coupled for receiving a fourth control signal, the fourth control signal controlling the fourth switching means for operating substantially 180 degrees out of phase with the third switching means;

first inductor storage means coupled between the first and second switching means and the output terminal for providing a first current to the output terminal; and

second inductor storage means coupled between the third and fourth switching means and the output terminal for proving a second current to the output terminal;

wherein a mutual inductance between the first and second inductor storage means has a coupling coefficient greater than 0.5.

4. A DC-to-DC converter for converting an input voltage having a first magnitude into an output voltage having a second magnitude, comprising:

transformer means having first and second windings wound about a common core such that a mutual inductance exists between the first and second windings, the first and second windings coupled for providing the output voltage;

first switching means coupled for switching the first winding between the input voltage and a reference voltage; and

second switching means coupled for switching the second winding between the input voltage and the reference voltage such that the first winding is coupled to the input voltage while the second winding is coupled to the reference voltage and the first winding is coupled to the reference voltage while the second winding is coupled to the input voltage.

5. The DC-to-DC converter according to claim 4 wherein the first and second switching means are first and second legs, respectively, of an H-bridge driver.

6. The DC-to-DC converter according to claim 5 wherein first and second currents flowing through the first and second windings, respectively, are trapezoidal waveforms 180 degrees out of phase.

7. The DC-to-DC converter according to claim 6 wherein the mutual inductance has a coupling coefficient greater than 0.5.

8. The DC-to-DC converter according to claim 7 further comprising a filter coupled for reducing ripple in the output voltage.